Conveners
Section 1. Experimental and theoretical studies of the properties of atomic nuclei
- Egor Zemlin (Saint Petersburg State University, Russia)
Section 1. Experimental and theoretical studies of the properties of atomic nuclei
- Dmitrii Nesterov (St Petersburg State University (RU))
Section 1. Experimental and theoretical studies of the properties of atomic nuclei
- Tatiana Lazareva (St Petersburg State University (RU))
Section 1. Experimental and theoretical studies of the properties of atomic nuclei: Few-Body Problem in Physics: Theory and Solution Methods
- Sergey Yakovlev (St Petersburg State University)
Section 1. Experimental and theoretical studies of the properties of atomic nuclei
- Vladimir Kovalenko (St Petersburg State University (RU))
Section 1. Experimental and theoretical studies of the properties of atomic nuclei
- Daria Prokhorova (St Petersburg State University (RU))
$^{13}$C is a good example of a “normal” nucleus that is well described in the framework of the shell model. Its level scheme is reliably determined up to excitation energies ~ 10 MeV. However, not so long ago, in the framework of the development of the theory of the α-condensation in light nuclei (αBEC), the existence of exotic cluster states in light nuclei with a significantly increased, by...
Light hypernuclei are a natural laboratory for studying $YN$ and $YY$ interactions [1]. The repulsive nature of the $\Lambda N$ interaction leads to the fact that bound states in light nuclei are generated due to the $N-Y-N$ interaction. The decisive role in this interaction is played by the $\Lambda N\to \Sigma N$ conversion of one type of hyperons into another. Experimental data on hyperon...
In recent decades, research related to low-energy nuclear physics has shown two basic trends. In experimental research, there has been a rapid transition from the study of stable and long-lived nuclei to the study of exotic, including nucleon-unstable systems. In theoretical research, an increasing place is occupied by high-precision microscopic approaches, in particular ab initio (from first...
The Quantum Electrodynamics theory for bound states at finite temperatures is discussed. The details of theory can be found in [1] where the derivation of thermal photon propagator in different forms and gauges is presented. The constructed theory is used to find the "thermal Coulomb interaction" and its asymptotic at large distances. Finally, the thermal effects of the lowest order in the...
Presently, the nuclear energy density functional theory is known as the most convenient and powerful theoretical tool for the calculation of the properties of nuclei throughout the nuclear chart. In this work, large-scale calculations are performed using the self-consistent Hartree-Fock-Bogoliubov method [1-2] for even-even nuclei between $8\leq Z\leq 114$. The Skyrme-type functionals are used...
I.N. Borzov 1,2
1 National Research Centre “Kurchatov Institute”, 123182, Moscow, Russia
2Bogolubov Laboratory of Theoretical Physics, Joint Institute of Nuclear Research, 141980,
†E-mail: Borzov_IN@nrcki.ru, cc: ibor48@mail.ru
Including the light neutron-rich nuclei to the r-process network is known to change the resulting heavy element abundances [1]. However, large-scale predictions of...
In strangeness nuclear physics, exotic hypernuclei with a proton or neutron excess are of particular interest now [1]. Such systems loosely studied experimentally so far can be produced in heavy ion collisions [2] at NICA complex developed at JINR. Properties of exotic hypernuclei can bring new knowledge on subtle features of the hyperon-nucleon and hyperon-nucleus interactions. Specifically,...
The unbound heavy helium isotope 9He has one of the largest neutron-to-proton ratios. In spite of a significant number of experimental and theoretical works, the problem of the spectroscopy of 9He remains open [1, 2]. Even for the ground state, there is uncertainty in determining the resonance energy and spin-parity (1- or 1+). The situation with the excited states of 9He is also uncertain....
I.N. Borzov 1,2, S.V. Tolokonnikov1,3
1 National Research Centre “Kurchatov Institute”, Moscow, Russia
2Bogolubov Laboratory of Theoretical Physics, Joint Institute of Nuclear Research, Dubna, Russia
3 Moscow Institute of Physics and Technology (National Research University), Dolgoprudny, Russia
†E-mail: Borzov_IN@nrcki.ru, cc: ibor48@mail.ru
Fully self-consistent study of the...
In Ref. [1], the $\gamma\gamma$-decay of a nuclear transition in competition with an allowed $\gamma$-decay has been discovered. This is the observation of the $\gamma\gamma$-decay of the first excited $J^{\pi}=11/2^{-}$ state of $^{137}$Ba directly competing with an allowed $\gamma$-decay to the $J^{\pi}=3/2^{+}$ ground state.The branching ratio of the competitive $\gamma\gamma$-decay of the...
One of the most striking discoveries in nuclear physics made at the end of the last century was the discovery of the neutron halo in the ground states of some light nuclei located near the neutron stability boundary.
The discovery of the halo led to a revision of many existing ideas in nuclear physics. The purpose of this research is to search and study halo in isobar - analog states of light...
The asymptotic normalization coefficients (ANCs) show how likely nucleons can stay in classically forbidden region and their knowledge if important for studying peripheral reactions such as proton capture in stellar environments.
We investigate relations between neutron, $C_n$, and proton, $C_p$, ANCs in mirror nuclear states for medium-mass nuclei, 40 ≤ A ≤ 100, using a two-body potential...
Neutron-rich nickel isotopes in vicinity of $^{78}Ni$ present an excellent opportunity to study the way in which neutron excess affects the properties of nuclear shell structure. Studies in this region of isotopes also provide insight in the nuclear mechanism of r-process responsible for their synthesis. The path of the consequent reactions constituting r-process is dictated by the shell...
The work is devoted to the description of the spectra of the lowest states and transition probabilities for the chain of zirconium isotopes $^{92-102}$Zr in the framework of the geometric collective model. As the mass increases, these isotopes undergo a transition from the spherical structure of the ground state to the deformed one; in $^{96}$Zr, the coexistence of spherical and deformed...
Neutron halo is one of the most intriguing properties of nuclei with sufficient excess of neutrons. Neutron halo was first observed experimentally in $^{11}Li$. The giant neutron halo of more than two neutrons was predicted also theoretically in medium and heavy mass nuclei near the neutron drip line, in particular in Ca, Zr, Ce. The halo and giant halo forms in $^{186-190}Ce$ and...
Semenov S.V.1, Khruschov V.V.1, Fomichev S.V.1
1 National Research Center "Kurchatov Institute", Moscow, Russia, 123182
E-mail: Semenov_SV@nrcki.ru
It is presented the calculation of the amplitude of 22 decay of 82Se on the basis of High-States Dominance (HSD) and Single-State Dominance (SSD) mechanisms [1]. The ground state of the intermediate nucleus 82Br for 22 decay of 82Se...
The pairing energies (PE) of nonmagic atomic nuclei with $A \geq 50$ can be derived from the odd nuclei masses $M$ provided it is possible to present $M$ as a sum of two terms [1]:
1) a smooth function of nucleon numbers having the same form of Tailor series expansion for even-even and odd nuclei;
2) PE: $P_{n}\left(N^{\prime}, Z\right)$ and $P_{p}\left(N, Z^{\prime}\right)$, where...
The recent detection of the gravitational wave GW170817, accompanied by a $\gamma$-ray burst and electromagnetic afterglow from the merger of neutron-star binary, has opened a new era of nuclear astrophysics. With neutron stars as a predominant laboratory for testing infinite nuclear matter, it has become easy to fine-tune the equation of the state (EoS) of nuclear matter using observational...
We study general convergence trends of binding energy calculations in oscillator basis depending on two basis parameters, the oscillator frequency, $\hbar\Omega$, and maximal oscillator quanta, $N$. We propose and test a new method which suggests extending the Hamiltonian matrix by the kinetic energy matrix elements. We study also convergence of calculations with smoothed potential matrix...
In this work we modify the Davydov-Chaban Hamiltonian describing the collective motion of $\gamma$-rigid atomic nuclei by allowing the mass to depend on the nuclear deformation. We construct Z(4)-DDM (Deformation-Dependent Mass) model by considering the Davidson potential, and solve the problem by techniques of asymptotic iteration method (AIM). We compare the results of the calculated...
All the enhancements of the P-violation effects in γ-transitions between the compound-nucleus states were analyzed in the classical paper [1] by I.S. Shapiro. The source of these effects is the weak interaction $V_W$ leading to the fact that the wave function $\psi$ of this state contains, besides the wave function of a definite parity $\psi_1$ , the small admixture of the opposite parity...
Estimates for experimentally unknown nuclear masses are obtained by a phenomenological approach based on a local mass relation for the residual neutron-proton interaction. The local mass relations method provides both high accuracy of isotope mass predictions and mathematical simplicity of calculations [1, 2]. Results based on different databases AME2012-2020 [3] are presented. Neutron-rich...
The self-consistent method for studying second-order anharmonic effects, within the framework of many-body quantum theory, is used for the first time to investigate the role of spin-spin forces in the probabilities of transitions between low-lying one-phonon states. Our approach includes accounting for: 1) self-consistency between the mean field and effective interaction based on the use of...
The effect is studied within a properly modified version of the continuum-random-phase-approximation (cRPA). Numerical results are obtained for the Gamow-Teller (GT) strength distribution in $^{208}Bi$. For this distribution, the experimental data concerned with the main-peak energy and the respective fraction of the Ikeda sum rule ($x_{peak}^{(-)}$) [1], and also the low-energy part...
This paper develops the first experience of using a fuzzy hybrid network model for the systematics of nuclear radii [1]. The root-mean-square charge radii of atomic nuclei measured by different methods are collected in the NuRa database [2]. A good result for the radii of all nuclei is given by the parametrization (the smooth curve in Fig.1).)
$R=(r_0+r_1 A^{1/3})\cdot A^{1/3}$ , if ...
In some nuclei, there are metastable states with "anomaly" long lifetimes, called nuclear isomers [1]. The report mentions the main events of the history of the discovery and research of the phenomenon of nuclear isomerism. The properties of isomeric states with a lifetime of more than 1 second (605 isomers in 548 nuclides) are considered on the base of the ENSDF 2021 file [2].
Studying the...
We present investigations of resonant states of exotic $^7$He nucleus and calculations of bound states and resonances of $^9$Li nucleus. Our results are obtained within an analysis of the $S$-matrix based on calculations within the no-core shell model (SS-HORSE-NCSM approach [1, 2]) using the realistic nucleon-nucleon interaction Daejeon16 [3].
Results for the $5/2^-$ and low-lying $3/2^-$...
We analyze sub-barrier heavy ion fusion reactions based on the coupled-channels description with the correct incoming wave boundary conditions, implemented by means of the finite element method. With the aid of the Woods-Saxon potential
the experimental cross sections and the so-called S factors of these reactions are remarkably well reproduced within the sudden approximation approach with...
Scattering problem for three-body systems is of great importance for many areas of physics. The complicated boundary conditions at large distances, especially for Coulomb potentials, are a major difficulty for studying of this problem [1]. While several methods have been developed for the solution to this problem, mathematically sound and computationally effective approaches are still in...
The states of the Be$^{11}$ nucleus as a core of Be$^{10}$ plus a neutron are studied in [1, 2], as well as many others. The Be$^{10}$ nucleus is an almost ideal object for studying the effects associated with the non-spherical shape of the nucleus. It has the largest deformation parameter for stable and long-lived nuclei. Usually the coupled channel method is used, the problem is reduced to a...
The interest to weakly-bound triatomic systems is stimulated by their connection with Efimov physics. There is a variety of systems including helium and helium-alkali triatomic molecules [1] whose states are close to Efimov regime. Some of these systems have bound states with nonzero orbital momentum. These latter states are much less studied than the states with the zero angular...
Asymptotic normalization coefficients (ANC) are fundamental nuclear characteristics important both in nuclear reaction and nuclear structure physics. The role of ANCs is especially substantial in determining the cross sections for astrophysical nuclear reactions inaccessible for direct measurement due to the large Coulomb barrier [1]. ANCs are on-shell observables, as distinct from the...
By a quantum speed limit one usually understands an estimate on how
fast a quantum system can evolve between two distinguishable states.
The most known quantum speed limit is known in the form of the
celebrated Mandelstam-Tamm inequality that bounds the speed of the
evolution of a state in terms of its energy dispersion. In contrast
to the basic Mandelstam-Tamm inequality, we are...
Different approaches which employ discretization of continuum, for example, by projecting the operators and wave functions into some finite $L_2$ basis, are widely used nowadays as efficient techniques to solve the scattering problems. Here we discuss how to extract information about scattering from the discretized spectra of unperturbed and total Hamiltonians. It is shown that if the discrete...
The asymptotic form of the wave function of a three-particle system interacting via Coulomb potentials in the continuum is described. The hyperradial asymptotic behavior of the wave function is found by study the weak asymptotic of the three-body wave function [1,2] and then applying to the asymptotic solutions of the Schroedinger equation in the hyper-spherical representation. The perspective...
Sequences of small volume samples of $n \leq 10$ numbers of reference ${k_{j}}$ particle fluxes with mean $0 \leq \bar{k} \leq 5$ correspond to random vectors $(\mathrm{RV}-v(.)$ ) of frequencies $v_{j}\left(k_{j}\right)$ of values $k_{j}: v(.)=\left(v_{0}, v_{1}, \ldots, v_{l}\right), n=\sum_{j=0}^{i} v_{j}\left(k_{j}\right)$ and $\mathrm{RV}$ of relative frequencies $v_{j}^{\prime}(.)=v_{j}...
The self-consistent Theory of Finite Fermi Systems (TFFS) [1,2] is consistently generalized for the case of accounting for phonon coupling (PC) effects in the energy region of pygmy- and giant multipole resonances (PDR and GMR) in magic nuclei with the aim to consider particle-hole (ph) and both complex 1p1h⊗phonon and two-phonon configurations. The article is the direct continuation and...
Isobaric analog resonances (AR) are investigated within the framework of the
microscopic theory of finite Fermi systems (TFFS) and in an approximate approach.
These studies began about 50 years ago [1–3] and are currently being successfully
continued in the self-consistent TFFS approach [4].
The calculations were performed for a large number of spherical and deformed
nuclei, and the...
We investigate the Coulomb breakup of $^{11}$Be halo nuclei on a heavy target from intermediate (70 MeV/nucleon) to low energies (5 MeV/nucleon) within the non-perturbative time-dependent approach. The convergence of the computational scheme is demonstrated in this energy range including \textit{n}+$^{10}$Be low-lying resonances in different partial and spin states. We have found a...
Being a microscopically based extension of the standard [1] and nonstandard [2] versions of the continuum-random-phase approximation (cRPA), by taking the spreading effect into account, the semi-microscopic particle-hole (p-h) dispersive optical model (PHDOM) has been proposed [3] and successfully implemented for describing properties of various giant resonances (GRs) in medium-heavy mass...
The large-angle proton-deuteron (pd) scattering at intermediate energies 200-1000 MeV is a long-standing puzzle. While the small-angle scattering can be described well by the Glauber diffraction model or, at energies Tp < 400 MeV, by the exact solution of Faddeev equations, the strong discrepancies between theoretical predictions and experimental data at large angles need a careful...
The semi-microscopic particle-hole dispersive optical model (PHDOM), originally formulated and successfully implemented for describing main properties of various giant resonances in medium-heavy closed-shell nuclei (see Ref. [1] and references therein), is extended to account for nucleon pairing in open-shell spherical nuclei. In the present work (which is a direct continuation of the...
The study of nuclear giant resonances has long been a subject of extensive theoretical and experimental research. The multipole response of nuclei far from the beta-stability line and the possible occurrence of exotic modes of excitation present a growing field of research. In particular, the study of the isoscalar giant monopole resonances (ISGMR) in neutron-rich nuclei is presently an...
The study of the scattering of hadrons with nuclei is a key element of the theory of the atomic nucleus and nuclear reactions. This is a test that allows one to investigate both the structure of the nucleus and the nuclear interaction. The best studied both experimentally and theoretically is the scattering of protons. For example, a large cycle of studies on the structure of light exotic...
We propose a quark model of nuclear structure, where quark correlations lead to nucleon--nucleon correlaions and arrangement of them into lattice--like structure.
The model is based on the quark model of nucleon structure, Strongly Correlated Quark Model (SCQM), in which valence quarks
are strongly correlated within a nucleon. Nuclei are constructed due to junctions of SU(3) color fields of...
THE EXPERIMENTAL ARRANGEMENT AND PRELIMINARY RESULTS OF SEARCH FOR LIGHT NEUTRON CLUSTERS IN 235U NUCLEI DECAY
Dudkin G.N., Chumakov D.K., Varlachev V.A.
National Research Tomsk Polytechnic University, Tomsk, Russia;
E-mail: dkc1@tpu.ru
The problem of light clusters of neutrons existence, such as dineutron, tetraneutron, hexaneutron, octaneutron is under study for at least 60...
Systematic study of the evolution of the nuclear charge radii, deformation, configurations and other ground and isomeric states characteristics near the proton shell closure (Z = 82) is actual and important task. It will enable to construct the two-dimensional picture (with N and Z varied) of the changes of these fundamental nuclear characteristics.
One of the most efficient method for...
In transactinide nuclei the collectivity of low-lying states is greatly developed. This manifests itself in both small (from 42 to 50 keV) of the energies of lowest states $E(2^+_1)$, and in the weak indirect manifestation of quasiparticle excitations. Because of the high collectivity, the yrast-band states in transuranium nuclei can be successfully described [1] up to high spins in the...
В настояшей работе исследуются неадиабатические эффекты в октупольноколебательных полосах ядра ${ }^{156} \mathrm{Gd} .$ Соответствующие экспериментальные данные оценены и систематизированы в работе [1]. В частности, в спектре ${ }^{156} \mathrm{Gd}$ выделены четыре ротационные полосы отрицательной четности с квантовыми числами оснований $\mathrm{K}^{\pi}=0^{-}, 1^{-}$ и $2^{-} .$ Нижайшая из...
The integrated quantities of beta-decay (such as half-live and probability of delayed (multi) neutron emission P1(x)n) are in general the first available for very neutron-rich nuclei. Even at low production yield down to a few counts per second, their measurements can be achieved using high-sensitivity or high-efficiency detectors. In those conditions, they can be truly viewed as a first step...
We present an analysis of all the known superdeformed (SD) bands in 193Pb using the modified variable moment of inertia (VMI) model to obtain the values of unknown band-head spin (I0) along with the level spin. The band-head spin so estimated is not known experimentally in band-7, 8 and 9. A total of 9 experimentally known SD bands of 193Pb have been analyzed. Quantitatively good results of...
In laser plasma, stimulated de-excitation of the 186mRe isomer (T1/2, m = 2.0∙105 y) was observed from the time dependence of the intensity I137 of 137 keV gammas from the decay of the ground state of the 186Re nucleus after laser irradiation of the 186mRe target [1]. The nonmonotonicity of this time dependence made it possible to assume the existence in the 186Re nucleus of a new low-lying...
Potential energy surfaces in $(\beta,\gamma)$ coordinates and equilibrium ground-state deformations of nuclei with $50 \le A \le 240$ are calculated using a simple model based on the Mottelson--Nilsson approach where the potential energy of deformation is taken as a sum of occupied levels in an ellipsoidally deformed one-particle potential well. Parameters of the real part of the global...
In this talk, we will present the first measurement of the neutron skin of cesium and iodine using electroweak probes, coherent elastic neutrino-nucleus scattering and atomic parity violation. This measurement, differently from hadronic probes, is model-independent and suggests a preference for nuclear models which predict large neutron skin values, with implications that range from neutron...
We continue our explorations [1] of the electromagnetic properties of the deuteron with help of the method of unitary clothing transformations (UCT) [2,3]. It is the case, where one has to deal with the matrix elements $\langle \mathbf P', M'| J^{\mu}(0) | \mathbf P, M \rangle$ (to be definite in the lab. frame). Here the operator $J^{\mu}(0)$ is the Nöther current density $J^{\mu}(x)$ at the...
Let us remind that in the one-photon-exchange approximation (OPEA) the elastic e-d scattering amplitude is proportional to the contraction $T(ed \rightarrow e' d') = \varepsilon_\mu (e,e')\langle \mathbf q\, M' | J^\mu(0) | \mathbf 0\, M \rangle$ where we have introduced the notation $\varepsilon_\mu (e,e') = \bar u_{e'}(k') \gamma_\mu u_e(k)$. Here the operator $J^{\mu}(0)$ is the Nöther...
We will show a detailed derivation of matrix elements (in momentum space) of the three-nucleon interaction operator [1] built up within the field theoretical approach based on the method of unitary clothing transformations (UCTs) [2,3,4]. As before, we start from the instant form of relativistic dynamics after Dirac with the total field Hamiltonian $H$ for Yukawa-type couplings between $\pi...
